In recent years, games have become commonplace which are played by installing a game program on a portable device from a server via a communication network. Such games include games in which two or more players can participate (so-called “social games”). There are games in which players cannot only battle against or help each other, but also communicate with each other.
In a portable device such as a smartphone, a communication environment and device specifications are more limited than a PC and the like, and therefore a data amount transferable among devices of two or more players and the number of objects drawable in a single device at the same time are limited. Therefore, in a game for portable devices, the number of players playable in the same game space at the same time is limited, differently from an online game referred to as MMO (Massively Multiplayer Online) where a large number of players connect to a server from devices such as PCs and the like.
As a device addressing such hardware limitations, Japanese Laid-open Patent Publication No. 2010-125222 (hereinafter, referred to as Patent Literature 1), for example, describes a game device, in which even a relatively small-scale hardware configuration such as a portable game device and the like can achieve game performance similarly to a network game. The game of Patent Literature 1 is a stand-alone type game progressing independently of other game devices, but in this game, mutual communication connection between an own game device and other game devices makes it possible to transfer game progress information. Therefore, in the game of Patent Literature 1, similarly to a network game, game progress of another game devices can be reflected in game progress of the own game device.
Further, “Clash of Clans” <URL:http://en.wikipedia.org/wiki/Clash_of_Clans> (hereinafter, referred to as Non-Patent Literature 1) describes an online game for portable devices, in which an object is arranged in a game space by an operation of a player and the object autonomously operates. In the game of Non-Patent Literature 1, players battle against each other on a one-to-one basis, differently from MMO where a large number of players can play a game on a wide range of single field map at the same time.